Attachments for harvesters have a conveyor device behind the cutter bars in order to feed the cut harvest over the entire width of the attachment to an intake channel of a grain conveyor. Frequently, the conveyor device is disposed in the middle. For example, intake augers may be used as conveyors, i.e., rollers having opposed auger flights, and/or conveyor belts. Attachments, which substantially use conveyor belts to convey the harvest to the intake channel, are referred to as belt cutting units. The conveyor belts of the belt cutting units convey the harvest in a gentler and more consistent manner to the intake channel than intake augers, in particular with smaller quantities of harvest. Belt cutting units are also typically lighter, which may allow for having very wide cutting units. Moreover, belt cutting units may make higher harvest outputs possible.
Thus, using a center belt for conveying the harvest to the intake channel, which is loaded with harvest by adjacent transverse conveyor belts, may assist the harvester. Further, the belt speed of the conveyor belts may be adjusted to improve the harvest output.
US 2015/0135675 A1 discloses a control of the conveyor belt speed as a function of the slope. The belt speeds of the center belt and the transverse conveyor belts can be adjusted individually as a function of the slope.